Ester of carboxylic acid is a kind of very important chemical raw material, pharmaceutical intermediates, fragrances, etc., and may also be used as liquid fuels, such as biodiesel and biogasoline. Biodiesel as people talk about today broadly means ester of carboxylic acid produced from aliphatic acids and small molecular alcohols. The well-known biodiesel is aliphatic esters of methanol, as methanol is the cheapest alcohol. Methyl carboxylates prepared from animal fat and vegetable oil are regarded as the most ideal substitute for diesel, because they contain neither sulfur aromatic compounds nor nitrogen aromatic compounds, and thus, when burning, will not produce sulfur oxides, nitrogen oxides and the like which are the most predominant environmental pollutants.
Nowadays, commercially available products of ester of carboxylic acid are almost all prepared from petroleum, coal, foodstuff as well as edible animal fat and vegetable oil as starting materials through a series of reactions. Particularly, the starting materials of the biodiesel used currently in large quantities are exclusively animal fat and vegetable oil which, as the traditional and customary human food, are already very short in view of population. As indicated by a UN statistical source in June, 2009, there are presently over 1 billion people in a state of famine. Therefore, it is deemed as a crime against humanity to take human food for other purposes.
Cellulosic biomass is the largest, annually renewable organic carbon resource on the earth. However, it is mostly discarded as waste. If a process is developed to prepare chemical raw materials, pharmaceutical intermediates, fragrances, etc., such as ester of carboxylic acid, by using cellulosic biomass as a starting material, then not only the starvation problem of a considerable proportion of the population will be solved due to substantially reduced consumption of foodstuff, but also the production cost of ester of carboxylic acid including biodiesel will be lowered somewhat along with the change of cellulosic biomass from waste to treasure.
Therefore, a process for preparing chemical raw materials, pharmaceutical intermediates, fragrances, etc. by refining cellulosic biomass, such as preparing ester of carboxylic acid from cellulosic biomass, is extremely important to sustainable development of human beings.